Process of opening and shaping tube-blanks



in) Model.) 2 Sheets Sheet 1. G. A. MARSHALL.

PROGESS OF OPENING AND SHAPING TUBE BLANKS. No. 389,586.

Patented Sept; 18, 1888.

2 SheetsSheet 2.

(No Model.)

0. AJMARSHALL.

rnocnss 0F OPENING AND SHAPING TUBE BLANKS. No. 389,586.

Patented Sept. 18, 1888.

N PETERS, Pholo-Lithognpher. Wfllnngtnn.

UNITED STATES PATENT OFFICE.

CHARLES A. MARSHALL, OF JOHNSTOVVN, PENNSYLVANIA.

PROCESS OF OPENING AND SHAPING TUBE-BLANKS.

SPECIFICATION forming part of Letters Patent No. 389,586, datedSeptember 18, 1888.

Application tiled January 30, 1888. Serial No. 262,334. (No model.)

process of opening flat metallic tube-blanks,

and is applicable to blanks of any metal such as brass, ingot-iron, orsteel-and is designed more particularly to shape hot solidsteeltube-blanks to approximately round or oval shapes, so that they may bedrawn over a mandrel or ball with least friction and'wear of ball andleast distortion of metal blank.

In the accompanying drawings, Figure 1 is a view in vertical sectionshowing the blank in side elevation. Fig. 2 is a view in crosssect-ionof the blank before opening. Figs. 3, 4., and 5 are-cross-sectionsshowing successive forms assumed by the blank at different stages of theprocess. Fig, 6 is a view in end elevation of the rolls. Fig. 7 is aviewin horizontal section ofboth rolls audblank. Fig. 8 is a Viewillustrating how the blank opens by edge pressure alone. Fig. 9 is aView in crosssection through the rolls B and tube.

In application Serial No, 197,194, process of making seamless tubes, 1have shown and described opening flat tubeblanks by passing themedgewise between pressurerolls, and mentioned that with wide tubeblanksguides may be used to advantage in the process. In opening by edgepressure without the use of guides it is not easy to open the blanksquite up to the crease orend of slit, or, it open at all up to thatpoint, the angle of opening is very small, requiring a portion of thecrease to be opened or spread through a wide angle by the subsequentmandreling operations. This causes severe wear on the mandrel at thoseplaces coming in contact with and lying aside the inwardly-curving andthe unopened parts near edge of blank, and adds to the resistanceagainst passage of tube over the mandrel, tending to cause the blank tostick on the ball or mandrel. Among tube-makers failures or wasters fromthis cause are known as stickers, and are a source of great loss unlessguarded against with all care.

This application more fully sets forth the mode of operation and bestmanner of using of guides. The guides shown in the drawings consist ofshort rolls It It, having their axes parallel to the plane of axes ofedgewise pressure rolls R; but other forms of guides may be used-forexample, fixed surfaces-this iuvention consisting more particularly inthe mode of application of pressure to the blank as it passes through.Rollerguides R B may or may not be driven. Generally speaking, it willnot be necessary to drive them. Edge-pressure rolls R R are driven.

It It are the entering-guides. These are placed close enough to rolls Rto embrace and laterally support the sides of blank F where it ispartially open. This will preferably be at a point a little closer tobite of rolls R than would be that point where they would just touch ablank which was being opened without the use of guides R. The blank,having been started open at one end, by wedging or other means, for afew inches in length, to form approximately as in Fig. 3, preferably notquite so wide, is inserted between R It to engage R R. The guides It Rperform two offices, one being to hold the entering blank straight andcentral, the other being to press inward the separated sides, and thuscause a thrusting strain from edge to edge of the blank. If guides R Itwere not used, the distance from G 0, Fig. 1, to where the blank wouldhave width 10, Fig. 3, would be greater than that shown, so that bytheir use in applying pressure to sides I prevent the blank from openingfreely as far back as it otherwise would do.

Guides It It, on leaving side of rolls, operate in substantially thesame way as just de scribed. In order to understand the action of theguides more clearly we will first examine the condition of the blank atbite of rolls, (0 0, Fig. 1.) Here there is pressure against the edgesof blank exerted by grooves g g of rolls It, and for as great a distancefrom edges as the trend of the metal is, substantially in the plane ofthe grooves g 9, this pressure is transmitted across the metal ofblankas a compressive stress; but this distance or parallel part of blank isvery short, and if we suppose the middle portion unrestrained sidewisethe reaction against pressure of rolls is supplied ultimately in part bythe resistance of the central metal to bending outward. Now such thinsheets are capable of but small resistance against bending when alreadyas much bent as is necessary in order to open the blank satisfactorily.The resistance against bending likewise is less as width 10 Fig. 1, isgreater. I have said that the resistance is in part supplied thus.Another and perhaps greater part is supplied by the resistance of theedges and unopened portions against bending as they approach closertogether from depth hat A A to depth h" at C 0. Also, there is a certainamount of compression from edge to edge carried around the sides whilethe blank is yet opened only to, say, form of Fig. 3. This compression,I have above stated, is preferably to be increased by action of guides RR Now, turning to guides R, they are so set as to restrain the sides, sothat 10 is less than 10, or less than the width of the blank would be ifit were opened by edge pressure alone to depth h without restraining thesides. This sets up compression in the four inclined quarters of blank qq, Fig. 3, making these parts act as A-braces, their resultant pressurestending to throw the edges of blank farther from each other, and socause depth It to be greater than depth h". It is to be observed thatthis action may not always throw the edge of the blank farther apart,but may expend itselfin producing a sharper bend in the metal close tothe edges, thus increasing the dihedral angle at the crease. It is thusseen that the edges of blank are held apart at B B by guides It R and atD D by guides R B", so that each angular portion of blank next to creaseis relatively to the rolls R R suspended as a beam and bent by the rollsat O G. A very simple experiment will convince one that this is afavorable condition for spreading the blank up to the extremity of thecrease or slit. Thus, c'rease a strip of paper to the form of aninverted V (A) in cross-seetion and support it so creased at theextremities of its length, then press down in the middle, when thetendency of the dihedral angle to become larger in the middle will beapparent.

It will be observed that by restraining the sides of blank near to thebite of rolls, as de; scribed, the width w" is less than it would bewere such restraint removed. This is favorable to my object, and mightbe attained by guides placed opposite to bite of rolls R It. In myapplication Serial No. 197,194 I have shown a way of shaping the groovesin rolls R R, substantially by making large grooves, having smallergrooves at bottom of said large grooves, to correspond with thesmallgrooves q of the drawings accompanying this application, which maywell accomplish the same purpose as guides placed at bite of rolls,though a further effect of such grooves is to scratch and otherwise markor injure the external surface of the blank.

The guides R It are preferably recessed, as shown, Fig. 9, of such shapeas to support and restrain the sides of blank for a considerable portionof depth at and near middle, and also to restrain the quarter-points qq, Fig. 9, from assuming a position too near the horizontal, which wouldweaken the reaction from edge to edge. Restraint onlyin the middle-ms,for example, by guides with plane surfaces or right cylindricalsurfaces-might result in a good general form of opened blank, which ispreferably an oblong with its longer axis in direction of the edges; yetthe freedom to bend at the quarter-points would result in diminishingthe reactions which tend to throw the edges apart, and hence render theeffect of edgingrolls R R less perfect and the dihedral angle at creasesmaller.

For small sizes of blanks the guides R B may well be dispensed with,since the distance from bite of rolls to unopened part of blank is shortin case of such small blanks, and one chief function of guides RR-namely, to sustain edges apart ata point close to bite of rollsistherefore unnecessary; also, there is little or no danger of both sidesof small blanks ever buckling the same way when once started to bucklein opposite directions.

In the above description I have referred to the operation of the partsin connection with a flat unopened blank; but it is evident that thesame steps can be employed with a partlyopened blank or with a blankpreviously opened by edge pressure alone; and it is also evident thateitherset of rollers B B may be dispensed with and the advantages of theuse of the other set retained, and hence I would have it understood thatI do not confine myself to the construction and combinations of partsshown, as it is evident that numerous changes and modifications might beresorted to without departing from the spirit of my invention.

Having fully described my invention, what I claim as new, and desire tosecure by Letters Patent, is-

1. In the process of making tubes, the following steps, viz: passing theblank between edge-pressure rolls and supporting the sides of the blankWhile the latter is being opened by the edge-pressure rolls.

2. The process of opening and shaping tubeblanks, consisting,essentially, in passing the blank through a series of rolls adapted toexert pressure against four sides of the blank.

3. The process of opening and shaping tubeblanks, consisting,essentially, in passing the blank between edge-pressure rolls foropening the blank and supporting and shaping the sides of the blank asthe latter leaves the edgepressurc rolls, substantially as set forth.

4. The process of opening and shaping tubeblanks, consisting,essentially, in passing the blank between edgepressurc rolls for openingthe blank and supporting the sides of the blank at a point on theentering side a short distance from the bite of the edge-pressure rolls,subcaused to aproach each other, and restraining stantially as setforth. I the approach of the metal adjacent to the edges 5. The processof opening and shaping tube by external pressure applied to the sides ofthe r 5 blanks, consisting in passing the blank beblank. 7 5 tweenedge-pressure rolls and supporting and In testimony whereof I havesigned this shaping the blank as it enters and leaves the Ispecification in the presence of two subscribrolls at short distancesfrom the bite of the I ing witnesses.

rolls.

'6. The process of increasing the angle of CHAS MARSHALL [0 opening atedges of a previously-flat or par- Witnesses:

tiallyopened blank, consisting in applying G. F. DOWNING,

pressure to the edges, whereby the latter are S. G. NOTTINGHAM.

